System and Method for Content Aware Disk Extent Movement in RAID

ABSTRACT

A method, computer program product, and computer system for identifying, by a computing device, information associated with a relationship between a physical layer block and a virtual logic block for RAID storage. The information associated with the relationship between the physical layer block and the virtual logic block may be written within the RAID storage.

RELATED APPLICATIONS

This application claims priority to Russian Patent Application No.2019102395, filed on Jan. 29, 2019, the contents of which is hereinincorporated by reference in its entirety.

BACKGROUND

Generally, when referring to storage systems, the user data may beevenly distributed between drives belonging to a RAID massive (e.g.,Mapped RAID). Once a drive fails, the lost data may be recreated usingthe survived data and the corresponding code blocks. Typically, thespare drive is used to store the data rather than the failed one. In anexample Mapped RAID environment, the recreated data may be distributedbetween the healthy drives and the corresponding mappings may beupdated. Generally, the duration of the rebuild process may depend onthe amount of data to rebuild, which may increase as the amount of dataincreases.

BRIEF SUMMARY OF DISCLOSURE

In one example implementation, a method, performed by one or morecomputing devices, may include but is not limited to identifying, by acomputing device, information associated with a relationship between aphysical layer block and a virtual logic block for RAID storage. Theinformation associated with the relationship between the physical layerblock and the virtual logic block may be written within the RAIDstorage.

One or more of the following example features may be included. Theinformation associated with the relationship between the physical layerblock and the virtual logic block may be written within a stripe of theRAID storage. The information may include a back pointer from thephysical layer block to the virtual logic block. The back pointer may bewritten within the stripe of the RAID storage where data associated withthe physical layer block is written. It may be determined whether thevirtual logic block, referenced by the back pointer in the physicallayer block, includes a pointer to the physical layer block where theback pointer is written. The pointer to the physical layer block may bezeroed when the virtual logic block, referenced by the back pointer inthe physical layer block, does not include the pointer to the physicallayer block where the back pointer is written. Active data may becompacted at a target location, and the virtual logic blockcorresponding to the active data compacted at the target location may beupdated.

In another example implementation, a computing system may include one ormore processors and one or more memories configured to performoperations that may include but are not limited to identifying, by acomputing device, information associated with a relationship between aphysical layer block and a virtual logic block for RAID storage. Theinformation associated with the relationship between the physical layerblock and the virtual logic block may be written within the RAIDstorage.

One or more of the following example features may be included. Theinformation associated with the relationship between the physical layerblock and the virtual logic block may be written within a stripe of theRAID storage. The information may include a back pointer from thephysical layer block to the virtual logic block. The back pointer may bewritten within the stripe of the RAID storage where data associated withthe physical layer block is written. It may be determined whether thevirtual logic block, referenced by the back pointer in the physicallayer block, includes a pointer to the physical layer block where theback pointer is written. The pointer to the physical layer block may bezeroed when the virtual logic block, referenced by the back pointer inthe physical layer block, does not include the pointer to the physicallayer block where the back pointer is written. Active data may becompacted at a target location, and the virtual logic blockcorresponding to the active data compacted at the target location may beupdated.

In another example implementation, a computer program product may resideon a computer readable storage medium having a plurality of instructionsstored thereon which, when executed across one or more processors, maycause at least a portion of the one or more processors to performoperations that may include but are not limited to identifying, by acomputing device, information associated with a relationship between aphysical layer block and a virtual logic block for RAID storage. Theinformation associated with the relationship between the physical layerblock and the virtual logic block may be written within the RAIDstorage.

One or more of the following example features may be included. Theinformation associated with the relationship between the physical layerblock and the virtual logic block may be written within a stripe of theRAID storage. The information may include a back pointer from thephysical layer block to the virtual logic block. The back pointer may bewritten within the stripe of the RAID storage where data associated withthe physical layer block is written. It may be determined whether thevirtual logic block, referenced by the back pointer in the physicallayer block, includes a pointer to the physical layer block where theback pointer is written. The pointer to the physical layer block may bezeroed when the virtual logic block, referenced by the back pointer inthe physical layer block, does not include the pointer to the physicallayer block where the back pointer is written. Active data may becompacted at a target location, and the virtual logic blockcorresponding to the active data compacted at the target location may beupdated.

The details of one or more example implementations are set forth in theaccompanying drawings and the description below. Other possible examplefeatures and/or possible example advantages will become apparent fromthe description, the drawings, and the claims. Some implementations maynot have those possible example features and/or possible exampleadvantages, and such possible example features and/or possible exampleadvantages may not necessarily be required of some implementations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example diagrammatic view of a data movement processcoupled to an example distributed computing network according to one ormore example implementations of the disclosure;

FIG. 2 is an example diagrammatic view of a storage system of FIG. 1according to one or more example implementations of the disclosure;

FIG. 3 is an example diagrammatic view of a storage target of FIG. 1according to one or more example implementations of the disclosure;

FIG. 4 is an example flowchart of a data movement process according toone or more example implementations of the disclosure;

FIG. 5 is an example storage system layout according to one or moreexample implementations of the disclosure;

FIG. 6 is an example storage system layout according to one or moreexample implementations of the disclosure;

FIG. 7 are example storage system layouts according to one or moreexample implementations of the disclosure; and

FIG. 8 are example storage system layouts according to one or moreexample implementations of the disclosure.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION System Overview:

In some implementations, the present disclosure may be embodied as amethod, system, or computer program product. Accordingly, in someimplementations, the present disclosure may take the form of an entirelyhardware implementation, an entirely software implementation (includingfirmware, resident software, micro-code, etc.) or an implementationcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore, insome implementations, the present disclosure may take the form of acomputer program product on a computer-usable storage medium havingcomputer-usable program code embodied in the medium.

In some implementations, any suitable computer usable or computerreadable medium (or media) may be utilized. The computer readable mediummay be a computer readable signal medium or a computer readable storagemedium. The computer-usable, or computer-readable, storage medium(including a storage device associated with a computing device or clientelectronic device) may be, for example, but is not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, device, or any suitable combination ofthe foregoing. More specific examples (a non-exhaustive list) of thecomputer-readable medium may include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a digital versatile disk (DVD), a static randomaccess memory (SRAM), a memory stick, a floppy disk, a mechanicallyencoded device such as punch-cards or raised structures in a groovehaving instructions recorded thereon, a media such as those supportingthe internet or an intranet, or a magnetic storage device. Note that thecomputer-usable or computer-readable medium could even be a suitablemedium upon which the program is stored, scanned, compiled, interpreted,or otherwise processed in a suitable manner, if necessary, and thenstored in a computer memory. In the context of the present disclosure, acomputer-usable or computer-readable, storage medium may be any tangiblemedium that can contain or store a program for use by or in connectionwith the instruction execution system, apparatus, or device.

In some implementations, a computer readable signal medium may include apropagated data signal with computer readable program code embodiedtherein, for example, in baseband or as part of a carrier wave. In someimplementations, such a propagated signal may take any of a variety offorms, including, but not limited to, electro-magnetic, optical, or anysuitable combination thereof. In some implementations, the computerreadable program code may be transmitted using any appropriate medium,including but not limited to the internet, wireline, optical fibercable, RF, etc. In some implementations, a computer readable signalmedium may be any computer readable medium that is not a computerreadable storage medium and that can communicate, propagate, ortransport a program for use by or in connection with an instructionexecution system, apparatus, or device.

In some implementations, computer program code for carrying outoperations of the present disclosure may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Java®, Smalltalk, C++ or the like.Java® and all Java-based trademarks and logos are trademarks orregistered trademarks of Oracle and/or its affiliates. However, thecomputer program code for carrying out operations of the presentdisclosure may also be written in conventional procedural programminglanguages, such as the “C” programming language, PASCAL, or similarprogramming languages, as well as in scripting languages such asJavascript, PERL, or Python. The program code may execute entirely onthe user's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough a local area network (LAN) or a wide area network (WAN), or theconnection may be made to an external computer (for example, through theinternet using an Internet Service Provider). In some implementations,electronic circuitry including, for example, programmable logiccircuitry, field-programmable gate arrays (FPGAs) or other hardwareaccelerators, micro-controller units (MCUs), or programmable logicarrays (PLAs) may execute the computer readable programinstructions/code by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present disclosure.

In some implementations, the flowchart and block diagrams in the figuresillustrate the architecture, functionality, and operation of possibleimplementations of apparatus (systems), methods and computer programproducts according to various implementations of the present disclosure.Each block in the flowchart and/or block diagrams, and combinations ofblocks in the flowchart and/or block diagrams, may represent a module,segment, or portion of code, which comprises one or more executablecomputer program instructions for implementing the specified logicalfunction(s)/act(s). These computer program instructions may be providedto a processor of a general purpose computer, special purpose computer,or other programmable data processing apparatus to produce a machine,such that the computer program instructions, which may execute via theprocessor of the computer or other programmable data processingapparatus, create the ability to implement one or more of thefunctions/acts specified in the flowchart and/or block diagram block orblocks or combinations thereof. It should be noted that, in someimplementations, the functions noted in the block(s) may occur out ofthe order noted in the figures (or combined or omitted). For example,two blocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved.

In some implementations, these computer program instructions may also bestored in a computer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including instruction meanswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks or combinations thereof.

In some implementations, the computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operational steps to be performed (not necessarilyin a particular order) on the computer or other programmable apparatusto produce a computer implemented process such that the instructionswhich execute on the computer or other programmable apparatus providesteps for implementing the functions/acts (not necessarily in aparticular order) specified in the flowchart and/or block diagram blockor blocks or combinations thereof.

Referring now to the example implementation of FIG. 1, there is showndata movement process 10 that may reside on and may be executed by acomputer (e.g., computer 12), which may be connected to a network (e.g.,network 14) (e.g., the internet or a local area network). Examples ofcomputer 12 (and/or one or more of the client electronic devices notedbelow) may include, but are not limited to, a storage system (e.g., aNetwork Attached Storage (NAS) system, a Storage Area Network (SAN)), apersonal computer(s), a laptop computer(s), mobile computing device(s),a server computer, a series of server computers, a mainframecomputer(s), or a computing cloud(s). As is known in the art, a SAN mayinclude one or more of the client electronic devices, including a RAIDdevice and a NAS system. In some implementations, each of theaforementioned may be generally described as a computing device. Incertain implementations, a computing device may be a physical or virtualdevice. In many implementations, a computing device may be any devicecapable of performing operations, such as a dedicated processor, aportion of a processor, a virtual processor, a portion of a virtualprocessor, portion of a virtual device, or a virtual device. In someimplementations, a processor may be a physical processor or a virtualprocessor. In some implementations, a virtual processor may correspondto one or more parts of one or more physical processors. In someimplementations, the instructions/logic may be distributed and executedacross one or more processors, virtual or physical, to execute theinstructions/logic. Computer 12 may execute an operating system, forexample, but not limited to, Microsoft® Windows®; Mac® OS X®; Red Hat®Linux®, Windows® Mobile, Chrome OS, Blackberry OS, Fire OS, or a customoperating system. (Microsoft and Windows are registered trademarks ofMicrosoft Corporation in the United States, other countries or both; Macand OS X are registered trademarks of Apple Inc. in the United States,other countries or both; Red Hat is a registered trademark of Red HatCorporation in the United States, other countries or both; and Linux isa registered trademark of Linus Torvalds in the United States, othercountries or both).

In some implementations, as will be discussed below in greater detail, adata movement process, such as data movement process 10 of FIG. 1, mayidentify, by a computing device, information associated with arelationship between a physical layer block and a virtual logic blockfor RAID storage. The information associated with the relationshipbetween the physical layer block and the virtual logic block may bewritten within the RAID storage.

In some implementations, the instruction sets and subroutines of datamovement process 10, which may be stored on storage device, such asstorage device 16, coupled to computer 12, may be executed by one ormore processors and one or more memory architectures included withincomputer 12. In some implementations, storage device 16 may include butis not limited to: a hard disk drive; all forms of flash memory storagedevices; a tape drive; an optical drive; a RAID array (or other array);a random access memory (RAM); a read-only memory (ROM); or combinationthereof. In some implementations, storage device 16 may be organized asan extent, an extent pool, a RAID extent (e.g., an example 4D+1P R5,where the RAID extent may include, e.g., five storage device extentsthat may be allocated from, e.g., five different storage devices), amapped RAID (e.g., a collection of RAID extents), or combinationthereof.

In some implementations, network 14 may be connected to one or moresecondary networks (e.g., network 18), examples of which may include butare not limited to: a local area network; a wide area network or othertelecommunications network facility; or an intranet, for example. Thephrase “telecommunications network facility,” as used herein, may referto a facility configured to transmit, and/or receive transmissionsto/from one or more mobile client electronic devices (e.g., cellphones,etc.) as well as many others.

In some implementations, computer 12 may include a data store, such as adatabase (e.g., relational database, object-oriented database,triplestore database, etc.) and may be located within any suitablememory location, such as storage device 16 coupled to computer 12. Insome implementations, data, metadata, information, etc. describedthroughout the present disclosure may be stored in the data store. Insome implementations, computer 12 may utilize any known databasemanagement system such as, but not limited to, DB2, in order to providemulti-user access to one or more databases, such as the above notedrelational database. In some implementations, the data store may also bea custom database, such as, for example, a flat file database or an XMLdatabase. In some implementations, any other form(s) of a data storagestructure and/or organization may also be used. In some implementations,data movement process 10 may be a component of the data store, astandalone application that interfaces with the above noted data storeand/or an applet/application that is accessed via client applications22, 24, 26, 28. In some implementations, the above noted data store maybe, in whole or in part, distributed in a cloud computing topology. Inthis way, computer 12 and storage device 16 may refer to multipledevices, which may also be distributed throughout the network.

In some implementations, computer 12 may execute a storage managementapplication (e.g., storage management application 21), examples of whichmay include, but are not limited to, e.g., a storage system application,a cloud computing application, a data synchronization application, adata migration application, a garbage collection application, or otherapplication that allows for the implementation and/or management of datain a clustered (or non-clustered) environment (or the like). In someimplementations, data movement process 10 and/or storage managementapplication 21 may be accessed via one or more of client applications22, 24, 26, 28. In some implementations, data movement process 10 may bea standalone application, or may be anapplet/application/script/extension that may interact with and/or beexecuted within storage management application 21, a component ofstorage management application 21, and/or one or more of clientapplications 22, 24, 26, 28. In some implementations, storage managementapplication 21 may be a standalone application, or may be anapplet/application/script/extension that may interact with and/or beexecuted within data movement process 10, a component of data movementprocess 10, and/or one or more of client applications 22, 24, 26, 28. Insome implementations, one or more of client applications 22, 24, 26, 28may be a standalone application, or may be anapplet/application/script/extension that may interact with and/or beexecuted within and/or be a component of data movement process 10 and/orstorage management application 21. Examples of client applications 22,24, 26, 28 may include, but are not limited to, e.g., a storage systemapplication, a cloud computing application, a data synchronizationapplication, a data migration application, a garbage collectionapplication, or other application that allows for the implementationand/or management of data in a clustered (or non-clustered) environment(or the like), a standard and/or mobile web browser, an emailapplication (e.g., an email client application), a textual and/or agraphical user interface, a customized web browser, a plugin, anApplication Programming Interface (API), or a custom application. Theinstruction sets and subroutines of client applications 22, 24, 26, 28,which may be stored on storage devices 30, 32, 34, 36, coupled to clientelectronic devices 38, 40, 42, 44, may be executed by one or moreprocessors and one or more memory architectures incorporated into clientelectronic devices 38, 40, 42, 44.

In some implementations, one or more of storage devices 30, 32, 34, 36,may include but are not limited to: hard disk drives; flash drives, tapedrives; optical drives; RAID arrays; random access memories (RAM); andread-only memories (ROM). Examples of client electronic devices 38, 40,42, 44 (and/or computer 12) may include, but are not limited to, apersonal computer (e.g., client electronic device 38), a laptop computer(e.g., client electronic device 40), a smart/data-enabled, cellularphone (e.g., client electronic device 42), a notebook computer (e.g.,client electronic device 44), a tablet, a server, a television, a smarttelevision, a smart speaker, an Internet of Things (IoT) device, a media(e.g., video, photo, etc.) capturing device, and a dedicated networkdevice. Client electronic devices 38, 40, 42, 44 may each execute anoperating system, examples of which may include but are not limited to,Android™, Apple® iOS®, Mac® OS X®; Red Hat® Linux®, Windows® Mobile,Chrome OS, Blackberry OS, Fire OS, or a custom operating system.

In some implementations, one or more of client applications 22, 24, 26,28 may be configured to effectuate some or all of the functionality ofdata movement process 10 (and vice versa). Accordingly, in someimplementations, data movement process 10 may be a purely server-sideapplication, a purely client-side application, or a hybridserver-side/client-side application that is cooperatively executed byone or more of client applications 22, 24, 26, 28 and/or data movementprocess 10.

In some implementations, one or more of client applications 22, 24, 26,28 may be configured to effectuate some or all of the functionality ofstorage management application 21 (and vice versa). Accordingly, in someimplementations, storage management application 21 may be a purelyserver-side application, a purely client-side application, or a hybridserver-side/client-side application that is cooperatively executed byone or more of client applications 22, 24, 26, 28 and/or storagemanagement application 21. As one or more of client applications 22, 24,26, 28, data movement process 10, and storage management application 21,taken singly or in any combination, may effectuate some or all of thesame functionality, any description of effectuating such functionalityvia one or more of client applications 22, 24, 26, 28, data movementprocess 10, storage management application 21, or combination thereof,and any described interaction(s) between one or more of clientapplications 22, 24, 26, 28, data movement process 10, storagemanagement application 21, or combination thereof to effectuate suchfunctionality, should be taken as an example only and not to limit thescope of the disclosure.

In some implementations, one or more of users 46, 48, 50, 52 may accesscomputer 12 and data movement process 10 (e.g., using one or more ofclient electronic devices 38, 40, 42, 44) directly through network 14 orthrough secondary network 18. Further, computer 12 may be connected tonetwork 14 through secondary network 18, as illustrated with phantomlink line 54. Data movement process 10 may include one or more userinterfaces, such as browsers and textual or graphical user interfaces,through which users 46, 48, 50, 52 may access data movement process 10.

In some implementations, the various client electronic devices may bedirectly or indirectly coupled to network 14 (or network 18). Forexample, client electronic device 38 is shown directly coupled tonetwork 14 via a hardwired network connection. Further, clientelectronic device 44 is shown directly coupled to network 18 via ahardwired network connection. Client electronic device 40 is shownwirelessly coupled to network 14 via wireless communication channel 56established between client electronic device 40 and wireless accesspoint (i.e., WAP) 58, which is shown directly coupled to network 14. WAP58 may be, for example, an IEEE 802.11a, 802.11b, 802.11g, 802.11n,802.11ac, Wi-Fi®, RFID, and/or Bluetooth™ (including Bluetooth™ LowEnergy) device that is capable of establishing wireless communicationchannel 56 between client electronic device 40 and WAP 58. Clientelectronic device 42 is shown wirelessly coupled to network 14 viawireless communication channel 60 established between client electronicdevice 42 and cellular network/bridge 62, which is shown by exampledirectly coupled to network 14.

In some implementations, some or all of the IEEE 802.11x specificationsmay use Ethernet protocol and carrier sense multiple access withcollision avoidance (i.e., CSMA/CA) for path sharing. The various802.11x specifications may use phase-shift keying (i.e., PSK) modulationor complementary code keying (i.e., CCK) modulation, for example.Bluetooth™ (including Bluetooth™ Low Energy) is a telecommunicationsindustry specification that allows, e.g., mobile phones, computers,smart phones, and other electronic devices to be interconnected using ashort-range wireless connection. Other forms of interconnection (e.g.,Near Field Communication (NFC)) may also be used.

In some implementations, various I/O requests (e.g., I/O request 15) maybe sent from, e.g., client applications 22, 24, 26, 28 to, e.g.,computer 12. Examples of I/O request 15 may include but are not limitedto, data write requests (e.g., a request that content be written tocomputer 12) and data read requests (e.g., a request that content beread from computer 12).

Data Storage System:

Referring also to the example implementation of FIGS. 2-3 (e.g., wherecomputer 12 may be configured as a data storage system), computer 12 mayinclude storage processor 100 and a plurality of storage targets (e.g.,storage targets 102, 104, 106, 108, 110). In some implementations,storage targets 102, 104, 106, 108, 110 may include any of theabove-noted storage devices. In some implementations, storage targets102, 104, 106, 108, 110 may be configured to provide various levels ofperformance and/or high availability. For example, storage targets 102,104, 106, 108, 110 may be configured to form a non-fully-duplicativefault-tolerant data storage system (such as a non-fully-duplicative RAIDdata storage system), examples of which may include but are not limitedto: RAID 3 arrays, RAID 4 arrays, RAID 5 arrays, and/or RAID 6 arrays.It will be appreciated that various other types of RAID arrays may beused without departing from the scope of the present disclosure.

While in this particular example, computer 12 is shown to include fivestorage targets (e.g., storage targets 102, 104, 106, 108, 110), this isfor example purposes only and is not intended limit the presentdisclosure. For instance, the actual number of storage targets may beincreased or decreased depending upon, e.g., the level ofredundancy/performance/capacity required.

Further, the storage targets (e.g., storage targets 102, 104, 106, 108,110) included with computer 12 may be configured to form a plurality ofdiscrete storage arrays. For instance, and assuming for example purposesonly that computer 12 includes, e.g., ten discrete storage targets, afirst five targets (of the ten storage targets) may be configured toform a first RAID array and a second five targets (of the ten storagetargets) may be configured to form a second RAID array.

In some implementations, one or more of storage targets 102, 104, 106,108, 110 may be configured to store coded data (e.g., via storagemanagement process 21), wherein such coded data may allow for theregeneration of data lost/corrupted on one or more of storage targets102, 104, 106, 108, 110. Examples of such coded data may include but isnot limited to parity data and Reed-Solomon data. Such coded data may bedistributed across all of storage targets 102, 104, 106, 108, 110 or maybe stored within a specific storage target.

Examples of storage targets 102, 104, 106, 108, 110 may include one ormore data arrays, wherein a combination of storage targets 102, 104,106, 108, 110 (and any processing/control systems associated withstorage management application 21) may form data array 112.

The manner in which computer 12 is implemented may vary depending upone.g., the level of redundancy/performance/capacity required. Forexample, computer 12 may be configured as a SAN (i.e., a Storage AreaNetwork), in which storage processor 100 may be, e.g., a dedicatedcomputing system and each of storage targets 102, 104, 106, 108, 110 maybe a RAID device. An example of storage processor 100 may include but isnot limited to a VPLEX™ system offered by Dell EMC™ of Hopkinton, Mass.

In the example where computer 12 is configured as a SAN, the variouscomponents of computer 12 (e.g., storage processor 100, and storagetargets 102, 104, 106, 108, 110) may be coupled using networkinfrastructure 114, examples of which may include but are not limited toan Ethernet (e.g., Layer 2 or Layer 3) network, a fiber channel network,an InfiniBand network, or any other circuit switched/packet switchednetwork.

As discussed above, various I/O requests (e.g., I/O request 15) may begenerated. For example, these I/O requests may be sent from, e.g.,client applications 22, 24, 26, 28 to, e.g., computer 12.Additionally/alternatively (e.g., when storage processor 100 isconfigured as an application server or otherwise), these I/O requestsmay be internally generated within storage processor 100 (e.g., viastorage management process 21). Examples of I/O request 15 may includebut are not limited to data write request 116 (e.g., a request thatcontent 118 be written to computer 12) and data read request 120 (e.g.,a request that content 118 be read from computer 12).

In some implementations, during operation of storage processor 100,content 118 to be written to computer 12 may be received and/orprocessed by storage processor 100 (e.g., via storage management process21). Additionally/alternatively (e.g., when storage processor 100 isconfigured as an application server or otherwise), content 118 to bewritten to computer 12 may be internally generated by storage processor100 (e.g., via storage management process 21).

As discussed above, the instruction sets and subroutines of storagemanagement application 21, which may be stored on storage device 16included within computer 12, may be executed by one or more processorsand one or more memory architectures included with computer 12.Accordingly, in addition to being executed on storage processor 100,some or all of the instruction sets and subroutines of storagemanagement application 21 (and/or data movement process 10) may beexecuted by one or more processors and one or more memory architecturesincluded with data array 112.

In some implementations, storage processor 100 may include front endcache memory system 122. Examples of front end cache memory system 122may include but are not limited to a volatile, solid-state, cache memorysystem (e.g., a dynamic RAM cache memory system), a non-volatile,solid-state, cache memory system (e.g., a flash-based, cache memorysystem), and/or any of the above-noted storage devices.

In some implementations, storage processor 100 may initially storecontent 118 within front end cache memory system 122. Depending upon themanner in which front end cache memory system 122 is configured, storageprocessor 100 (e.g., via storage management process 21) may immediatelywrite content 118 to data array 112 (e.g., if front end cache memorysystem 122 is configured as a write-through cache) or may subsequentlywrite content 118 to data array 112 (e.g., if front end cache memorysystem 122 is configured as a write-back cache).

In some implementations, one or more of storage targets 102, 104, 106,108, 110 may include a backend cache memory system. Examples of thebackend cache memory system may include but are not limited to avolatile, solid-state, cache memory system (e.g., a dynamic RAM cachememory system), a non-volatile, solid-state, cache memory system (e.g.,a flash-based, cache memory system), and/or any of the above-notedstorage devices.

Storage Targets:

As discussed above, one or more of storage targets 102, 104, 106, 108,110 may be a RAID device. For instance, and referring also to FIG. 3,there is shown example target 150, wherein target 150 may be one exampleimplementation of a RAID implementation of, e.g., storage target 102,storage target 104, storage target 106, storage target 108, and/orstorage target 110. An example of target 150 may include but is notlimited to a VNX system offered by Dell EMC of Hopkinton, MA. Examplesof storage devices 154, 156, 158, 160, 162 may include one or moreelectro-mechanical hard disk drives, one or more solid-state/flashdevices, and/or any of the above-noted storage devices. It will beappreciated that while the term “disk” or “drive” may be usedthroughout, these may refer to and be used interchangeably with anytypes of appropriate storage devices as the context and functionality ofthe storage device permits.

In some implementations, target 150 may include storage processor 152and a plurality of storage devices (e.g., storage devices 154, 156, 158,160, 162). Storage devices 154, 156, 158, 160, 162 may be configured toprovide various levels of performance and/or high availability (e.g.,via storage management process 21). For example, one or more of storagedevices 154, 156, 158, 160, 162 (or any of the above-noted storagedevices) may be configured as a RAID 0 array, in which data is stripedacross storage devices. By striping data across a plurality of storagedevices, improved performance may be realized. However, RAID 0 arraysmay not provide a level of high availability. Accordingly, one or moreof storage devices 154, 156, 158, 160, 162 (or any of the above-notedstorage devices) may be configured as a RAID 1 array, in which data ismirrored between storage devices. By mirroring data between storagedevices, a level of high availability may be achieved as multiple copiesof the data may be stored within storage devices 154, 156, 158, 160,162.

While storage devices 154, 156, 158, 160, 162 are discussed above asbeing configured in a RAID 0 or RAID 1 array, this is for examplepurposes only and not intended to limit the present disclosure, as otherconfigurations are possible. For example, storage devices 154, 156, 158,160, 162 may be configured as a RAID 3, RAID 4, RAID 5 or RAID 6 array.

While in this particular example, target 150 is shown to include fivestorage devices (e.g., storage devices 154, 156, 158, 160, 162), this isfor example purposes only and not intended to limit the presentdisclosure. For instance, the actual number of storage devices may beincreased or decreased depending upon, e.g., the level ofredundancy/performance/capacity required.

In some implementations, one or more of storage devices 154, 156, 158,160, 162 may be configured to store (e.g., via storage managementprocess 21) coded data, wherein such coded data may allow for theregeneration of data lost/corrupted on one or more of storage devices154, 156, 158, 160, 162. Examples of such coded data may include but arenot limited to parity data and Reed-Solomon data. Such coded data may bedistributed across all of storage devices 154, 156, 158, 160, 162 or maybe stored within a specific storage device.

The manner in which target 150 is implemented may vary depending upone.g., the level of redundancy/performance/capacity required. Forexample, target 150 may be a RAID device in which storage processor 152is a RAID controller card and storage devices 154, 156, 158, 160, 162are individual “hot-swappable” hard disk drives. Another example oftarget 150 may be a RAID system, examples of which may include but arenot limited to an NAS (i.e., Network Attached Storage) device or a SAN(i.e., Storage Area Network).

In some implementations, storage target 150 may execute all or a portionof storage management application 21. The instruction sets andsubroutines of storage management application 21, which may be stored ona storage device (e.g., storage device 164) coupled to storage processor152, may be executed by one or more processors and one or more memoryarchitectures included with storage processor 152. Storage device 164may include but is not limited to any of the above-noted storagedevices.

As discussed above, computer 12 may be configured as a SAN, whereinstorage processor 100 may be a dedicated computing system and each ofstorage targets 102, 104, 106, 108, 110 may be a RAID device.Accordingly, when storage processor 100 processes data requests 116,120, storage processor 100 (e.g., via storage management process 21) mayprovide the appropriate requests/content (e.g., write request 166,content 168 and read request 170) to, e.g., storage target 150 (which isrepresentative of storage targets 102, 104, 106, 108 and/or 110).

In some implementations, during operation of storage processor 152,content 168 to be written to target 150 may be processed by storageprocessor 152 (e.g., via storage management process 21). Storageprocessor 152 may include cache memory system 172. Examples of cachememory system 172 may include but are not limited to a volatile,solid-state, cache memory system (e.g., a dynamic RAM cache memorysystem) and/or a non-volatile, solid-state, cache memory system (e.g., aflash-based, cache memory system). During operation of storage processor152, content 168 to be written to target 150 may be received by storageprocessor 152 (e.g., via storage management process 21) and initiallystored (e.g., via storage management process 21) within front end cachememory system 172.

Generally, when referring to storage systems, the user data may beevenly distributed between drives belonging to a RAID massive (e.g.,Mapped RAID). Once a drive fails, the lost data may be recreated usingthe survived data and the corresponding code blocks. Typically, thespare drive is used to store the data rather than the failed one. In anexample Mapped RAID environment, the recreated data may be distributedbetween the healthy drives and the corresponding mappings may beupdated. Generally, the duration of the rebuild process may depend onthe amount of data to rebuild, which may increase as the amount of dataincreases.

Usually, most of the associated storage arrays have software layers,which may use a log-based architecture, on top of RAID. In such examplearchitectures, the data is not typically rewritten in place, and thecontent of the block with the same address rewritten multiple times willgo to different places at every write. As such, some blocks of datawithin a stripe cannot be used anymore. Another example functionalitythat may invalidate some physical blocks is the off-line deduplicationand/or compression of data.

Generally, storage arrays balance the I/Os between drives. For instance,in case of solid state drives (SSDs), their wear level should bebalanced as well. The balancing is typically done by moving user data(e.g., in slice or segments) between RAID Extents (RE), where groups ofREs may be generally referred to as Rotation Groups or RAID Groups), andmoving the associated disk extents (DEs) between drives. Once a DE ismoved, the unreferenced data are moved together with the referenceddata. As such, this may increase the procedure time. Typically, thecompaction procedure may then move the data once again, which at leastin the case of SSDs, may consume drives wear. Therefore, as will bediscussed below, the present disclosure may maintain the back referencesfrom the blocks to the logical structures at the level the data iswritten (e.g., RAID), allowing the identification of the unused(unreferenced or incorrectly referenced) data blocks and compact thedata (e.g., before the movement). As a result, processing time may bereduced, and wear on the storage devices may be reduced to prolong theirlife.

As will be discussed below, data movement process 10 may at least help,e.g., improve an existing technological process necessarily rooted incomputer storage technology, in order to overcome an example andnon-limiting problem specifically arising in the realm of computer datastorage, which is integrated into the practical application of datastorage management. It will be appreciated that the computer processesdescribed throughout are integrated into one or more practicalapplications, and when taken at least as a whole are not considered tobe well-understood, routine, and conventional functions.

The Data Movement Process:

As discussed above and referring also at least to the exampleimplementations of FIGS. 3-8, data movement process 10 may identify 400,by a computing device, information associated with a relationshipbetween a physical layer block and a virtual logic block for RAIDstorage. Data movement process 10 may write 402 the informationassociated with the relationship between the physical layer block andthe virtual logic block within the RAID storage.

In some implementations, and referring at least to the exampleimplementation of FIG. 5, an example storage system layout 500 of MappedRAID is shown. In the example, storage system layout 500 may include aplurality of storage devices (e.g., disks), such as disk A, disk B, diskC, disk D, and disk E. As can be seen from FIG. 5, each disk includes anassociated disk extent (DE), which may be further organized into RAIDextents (REs) and again into RAID groups. It will be appreciated thatwhile the present disclosure (including FIG. 5) assumes a 1+1 MirroringRAID, the present disclosure may be adapted for other RAIDconfigurations (or similar) without departing from the scope of thepresent disclosure. As such, the use of a 1+1 Mirroring RAID, as well asthe other configurations disclosed (including Mapped RAID), should betaken as example only and not to otherwise limit the scope of thedisclosure.

In some implementations, data movement process 10 may identify 400, by acomputing device, information associated with a relationship between aphysical layer block and a virtual logic block for RAID storage. Forinstance, and referring at least to the example implementation of FIG.6, an example storage system layout 600 is shown. In the example,further assume FIG. 6 takes into account the storage system layout 500from FIG. 5. In the example, one or more logical structures is showndescribing a storage object, which looks like a tree. In this example,the logical structure is used to describe a logical unit number (LUN).As can be seen, the leaf nodes describes the data block corresponding toa certain address (logical block address or (LBA)). Usually, there isthe level of indirection between the leaf nodes and the physical blockscalled the physical layer block (PLB) and/or virtual logic block (VLB).These layers may allow the storage system (e.g., via data movementprocess 10) to change the physical location of the leaf node withoutupdating the tree. Such a structure may be useful (e.g., forrebalancing, deduplication, compression, etc.) since once the sameaddress is updated, data management process 10 may change the pointer tothe new physical location. In this case, data movement process 10 mayonly need to update the VLB. The other use cases may includededuplication and compression.

As can be seen in the key shown in the example FIG. 6, the portion ofDE_A_1 stored on diskA has used (i.e., referenced) physical blocks, andunused (i.e., unreferenced or incorrectly referenced) physical blocks.In the example, VLB1 points to PLB1 in DE_A_1 (in disk A of FIG. 5),VLB2 points to PLBN in DE_A_1, and VLB3 points to another DE on anotherdisk. As such, in the example, data movement process 10 may identify 400information (e.g., VLB and/or PLB pointer information) associated withthe relationship between the physical layer blocks (e.g., PLB1, PLB2,etc.) and the corresponding virtual logic blocks (e.g., VLB1, VLB2,etc.). In some implementations, the information may include a backpointer from the physical layer block to the virtual logic block. Forexample, with the concept of back pointers, components responsible forhousekeeping (e.g., such as garbage collectors) may identify if acertain physical block is referenced or not. This back pointer istypically a reference of the physical block to the corresponding VLB.Thus, in the example, data movement process 10 may identify 400information (e.g., VLB pointer information and/or PLB pointerinformation and/or back pointer information) associated with therelationship between the physical layer blocks (e.g., PLB1, PLB2, etc.)and the corresponding virtual logic blocks (VLB1 points to PLB1 inDE_A_1 and back pointer from BLB1 to VLB1, VLB2 points to PLBN in DE_A_1and a back pointer from PLBN to VLB2, and VLB3 points to another DE butthe back pointer from PLB2 points to VLB2, where PLB2 is no longer used.

In some implementations, data movement process 10 may write 402 theinformation associated with the relationship between the physical layerblock and the virtual logic block within the RAID storage. For instance,as noted above, a back pointer is typically a reference of the physicalblock to the corresponding VLB; however, back pointers typically mayexist on a layer that is higher than the RAID layer. That is, the RAIDlevel typically creates the address space, which is then distributedbetween containers of blocks, and these objects typically store the backpointers. Thus, these parts of information are not generally accessibleto the RAID level and cannot be used by it. By contrast, data movementprocess 10 may instead write 402 at least the back pointer informationwithin the RAID storage itself. As an example result, the information isaccessible to the RAID level and may be used by it.

In some implementations, the information associated with therelationship between the physical layer block and the virtual logicblock may be written within a stripe of the RAID storage, and in someimplementations, the back pointer may be written 402 within the stripeof the RAID storage where data associated with the physical layer blockis written. For instance, data movement process 10 may write 402 atleast the back pointer information within the RAID itself (e.g., to apredefined stripe of the RAID array, and/or may write 402 a least theback pointer information to the same stripe (or physical layer block)where the data associated with the physical layer block is written). Forexample, in some implementations, once the physical layer block iswritten, data movement process 10 may write the corresponding backpointer to it as well.

Referring to the example FIG. 7, there is shown a previous technique fordata movement in storage system layout 700 a. As shown in storage systemlayout 700 a, when a DE (e.g., DE_A_1) has to be moved, all of itscontent will be moved as well. However, as can be seen by the approachtaken by data movement process 10 in storage system layout 700 b, datamovement process 10 may only need to move the two data blocks which arecorrectly being used (referenced). For example, in some implementations,data movement process 10 may determine 404 whether the virtual logicblock, referenced by the back pointer in the physical layer block,includes a pointer to the physical layer block where the back pointer iswritten, and in some implementations, data movement process 10 may zero406 the pointer to the physical layer block when the virtual logicblock, referenced by the back pointer in the physical layer block, doesnot include the pointer to the physical layer block where the backpointer is written. For instance, periodically, data movement process 10may read the pointers and determine if the corresponding VLB points tothe corresponding physical layer block. If not, data movement process 10may zero the pointer. Once the rebalancing at the DE level is done, datamovement process 10 may read the pointers.

In some implementations, data movement process 10 may compact 408 activedata at a target location, and data movement process 10 may update 410the virtual logic block corresponding to the active data compacted atthe target location. For instance, still referring at least to FIG. 7and also at least to the example implementation of FIG. 8, an examplestorage system layout 800 of Mapped RAID is shown. In the example, datamovement process 10 may identify the active data in the physical layerblocks (by the above determination 404) and may compact 408 the activephysical layer blocks at the target location (e.g., shown at diskI).Data movement process 10 may then update 410 the VLBs corresponding tothe compacted data. In some implementations, the updating of the changedVLBs and switching between the old and new copies of the DE may be donetransitionally. As the result, the amount of data movement may decrease,both during the movement and at the garbage collecting phase.

It will be appreciated that data movement process 10 may run the garbagecollecting/compacting before the rebalancing; however, this may meanthat the data may have to be compacted at the source (e.g., in case ofSSDs the wear will be consumed) and then the compacted data may have tobe moved. In some implementations, data movement process 10 may writethe compacted data, thus, potentially eliminating wear (and time)required to compact the data at the source location. It will also beappreciated that while the term “disk” may be used, the term may beapplied to other types of storage devices as may be appropriate.

The terminology used herein is for the purpose of describing particularimplementations only and is not intended to be limiting of thedisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. As used herein, the language “at least one of A, B,and C” (and the like) should be interpreted as covering only A, only B,only C, or any combination of the three, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps (notnecessarily in a particular order), operations, elements, and/orcomponents, but do not preclude the presence or addition of one or moreother features, integers, steps (not necessarily in a particular order),operations, elements, components, and/or groups thereof

The corresponding structures, materials, acts, and equivalents (e.g., ofall means or step plus function elements) that may be in the claimsbelow are intended to include any structure, material, or act forperforming the function in combination with other claimed elements asspecifically claimed. The description of the present disclosure has beenpresented for purposes of illustration and description, but is notintended to be exhaustive or limited to the disclosure in the formdisclosed. Many modifications, variations, substitutions, and anycombinations thereof will be apparent to those of ordinary skill in theart without departing from the scope and spirit of the disclosure. Theimplementation(s) were chosen and described in order to explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various implementation(s) with various modifications and/or anycombinations of implementation(s) as are suited to the particular usecontemplated.

Having thus described the disclosure of the present application indetail and by reference to implementation(s) thereof, it will beapparent that modifications, variations, and any combinations ofimplementation(s) (including any modifications, variations,substitutions, and combinations thereof) are possible without departingfrom the scope of the disclosure defined in the appended claims.

What is claimed is:
 1. A computer-implemented method comprising:identifying, by a computing device, information associated with arelationship between a physical layer block and a virtual logic blockfor RAID storage; and writing the information associated with therelationship between the physical layer block and the virtual logicblock within the RAID storage.
 2. The computer-implemented method ofclaim 1 wherein the information associated with the relationship betweenthe physical layer block and the virtual logic block is written within astripe of the RAID storage.
 3. The computer-implemented method of claim2 wherein the information includes a back pointer from the physicallayer block to the virtual logic block.
 4. The computer-implementedmethod of claim 3 wherein the back pointer is written within the stripeof the RAID storage where data associated with the physical layer blockis written.
 5. The computer-implemented method of claim 4 furthercomprising determining whether the virtual logic block, referenced bythe back pointer in the physical layer block, includes a pointer to thephysical layer block where the back pointer is written.
 6. Thecomputer-implemented method of claim 5 further comprising zeroing thepointer to the physical layer block when the virtual logic block,referenced by the back pointer in the physical layer block, does notinclude the pointer to the physical layer block where the back pointeris written.
 7. The computer-implemented method of claim 6 furthercomprising: compacting active data at a target location; and updatingthe virtual logic block corresponding to the active data compacted atthe target location.
 8. A computer program product residing on acomputer readable storage medium having a plurality of instructionsstored thereon which, when executed across one or more processors,causes at least a portion of the one or more processors to performoperations comprising: identifying information associated with arelationship between a physical layer block and a virtual logic blockfor RAID storage; and writing the information associated with therelationship between the physical layer block and the virtual logicblock within the RAID storage.
 9. The computer program product of claim8 wherein the information associated with the relationship between thephysical layer block and the virtual logic block is written within astripe of the RAID storage.
 10. The computer program product of claim 9wherein the information includes a back pointer from the physical layerblock to the virtual logic block.
 11. The computer program product ofclaim 10 wherein the back pointer is written within the stripe of theRAID storage where data associated with the physical layer block iswritten.
 12. The computer program product of claim 11 wherein theoperations further comprise determining whether the virtual logic block,referenced by the back pointer in the physical layer block, includes apointer to the physical layer block where the back pointer is written.13. The computer program product of claim 12 wherein the operationsfurther comprise zeroing the pointer to the physical layer block whenthe virtual logic block, referenced by the back pointer in the physicallayer block, does not include the pointer to the physical layer blockwhere the back pointer is written.
 14. The computer program product ofclaim 13 wherein the operations further comprise: compacting active dataat a target location; and updating the virtual logic block correspondingto the active data compacted at the target location.
 15. A computingsystem including one or more processors and one or more memoriesconfigured to perform operations comprising: identifying informationassociated with a relationship between a physical layer block and avirtual logic block for RAID storage; and writing the informationassociated with the relationship between the physical layer block andthe virtual logic block within the RAID storage.
 16. The computingsystem of claim 15 wherein the information associated with therelationship between the physical layer block and the virtual logicblock is written within a stripe of the RAID storage.
 17. The computingsystem of claim 16 wherein the information includes a back pointer fromthe physical layer block to the virtual logic block.
 18. The computingsystem of claim 17 wherein the back pointer is written within the stripeof the RAID storage where data associated with the physical layer blockis written.
 19. The computing system of claim 18 wherein the operationsfurther comprise determining whether the virtual logic block, referencedby the back pointer in the physical layer block, includes a pointer tothe physical layer block where the back pointer is written.
 20. Thecomputing system of claim 19 wherein the operations further comprise:compacting active data at a target location; and updating the virtuallogic block corresponding to the active data compacted at the targetlocation.